Siege of Octoduron

The Siege of Octoduron (58 BC) was the first major battle of Julius Caesar's Gallic Wars. Caesar, the Proconsul of Cisalpine Gaul, set out with an army of Roman troops to halt the Helvetii migration westward and to destroy the tribe's threat to the Roman homeland. Caesar's army successfully stormed the city, ending the Helvetii tribe.

In 58 BC, Caesar mounted a series of campaigns against the Gallic barbarians with the goal of acquiring fame, glory, and plunder. He used Rome's alliance with the Aedui tribe to justify invading Gaul, as the Helvetii tribe threatened to invade Aedui lands as it migrated westwards. Caesar's 1,880-strong Legio II Primigenia marched around the Alps and into Switzerland, invading the Helvetic homeland. The Helvetii capital of Octoduron was besieged, with Chief Divico's army withdrawing from the mountain passes to defend the city. The Romans made use of ladders to storm the walls at several different points, and the assault on the westernmost wall managed to flank the preoccupied Helvetic warriors, who were busy trying to fight off other Roman assaults. The Romans attacked from multiple sides, slaughtering the trapped Helvetii. The Helvetii proceeded to retreat towards their town square, and they were attacked from two sides by Roman and Vocontii auxiliary infantry and Roman cavalry. The trapped Helvetic warriors made their last stand, and they were forced to capitulate. The Romans proceeded to loot the city and enslave the Helvetii, ending their threat to Rome.